1. Field of the invention
This invention relates to syringe needles and, more particularly, to a protective shield that covers a syringe needle until moved away from the needle by a positive movement.
2. Description of the Prior Art
Hypodermic syringes have needles through which fluid material is transferred between the hypodermic syringe and a patient or recipient. In the ordinary course of handling the hypodermic syringe, inadvertent contact with a needle may result in a puncture wound to an individual or to the bending of the needle or perhaps the blunting of the needle tip.
A puncture wound may result in the inadvertent transfer of material from the syringe to the person punctured, and such transfer may have drastic injurious or harmful results. In any event, the inadvertent contact may result in the contamination of the needle and the requirement for a change of the needle.
In the past, different types of safety caps or shield apparatus has been suggested for protecting the needle until the hypodermic syringe is ready for use.
Hypodermic needles of the prior art typically include a cap which is appropriately secured to the syringe and which must be physically removed prior to the use of the syringe. The physical removal is accomplished by a longitudinal or axial pull on the cap until the cap is past the end of the needle. The cap is then moved to the side and discarded. It will be noted that the user moves generally parallel to the needle as the user grasps the cap. If a sideways movement of the cap is made too soon, the needle may be bent.
There are also shield elements which include an outer syringe cylinder which moves axially on the syringe to expose the needle. The shield cylinder is secured by a twist lock type mechanism. Such twist lock mechanism is typically not used with a syringe larger than about twelve milliliters because the twist lock mechanism is not strong enough to withstand axial hits on the tip of the shield.
The apparatus of the present invention also includes a smaller diameter than the syringe barrel and the apparatus is closely linked to the needle base. These features prevent the needle shield from being pushed over the syringe body and from exposing the needle.
Other types of guard elements or assemblies also have been suggested. For example, U.S. Pat. No. 3,658,061 (Hall) disclosed a needle guard which is secured to the base of a needle and which pivots away from the needle in order to use the needle.
U.S. Pat. No. 4,623,336 (Pedicano et al.) discloses a needle sheath which resemble a funnel with a cap. The syringe is inserted into the conical portion of the funnel, with the needle extending into the conical extension or cylindrical portion for protection. The apparatus is designed to be used only once, and after use the cap is placed over the funnel end and is locked in place so that the apparatus may not be used again.
U.S. Pat. No. 4,747,836 (Luther) discloses a needle guard which is rotatably mounted to the base of the needle. The guard includes a longitudinal slot extending on the cylinder, and the cylinder is in turn secured to a semicircular element axially aligned with the needle. The slot in the cylinder is rotated on the needle to allow the needle to be removed from the apparatus. After use, the apparatus is placed on the needle again, and the slot is rotated away from the needle so that the needle is essentially fully enclosed.
U.S. Pat. No. 4,820,277 (Norelli) discloses a pivoting safety cover which includes a pair jaw members that fold over the needle and which pivot away from the needle. The two jaw elements pivot about 180 degrees away from the needle to allow the needle, and the syringe, to be used.
U.S. Pat. No. 4,838,871 (Luther) is similar to the '836 (Luther) Patent discussed above.
U.S. Pat. No. 4,886,503 (Miller) discloses a pivoting needle guard which includes a rupturable plastic film closing one part of the guard. As the guard or cover pivots away from the needle, the plastic film ruptures to expose the needle and to allow the needle and syringe to be used.
U.S. Pat. No. 4,921,489 (Frizzell) discloses another shield for a hypodermic needle which includes a pair of flat members which are hinged to a plate. The flat members are hinged to the plate and they move from a retracted position adjacent to a central sheath to an open position in which they provide a shield for the fingers of the user of the apparatus. The sheath also pivots away from the needle to allow the syringe and needle to be used.
U.S. Pat. No. 4,944,397 (Miller) discloses another type of sheath apparatus for hypodermic needle in which the sheath pivots relative to the needle. The sheath comprises a covering with a relatively opening in the covering. The covering is closed by a manually strippable tape. The tape is removed prior to the use of the needle, and the cover is then pivoted away from the needle for use.
U.S. Pat. No. 4,944,731 (Cole) disclosed another type of shield apparatus which uses a pair of pivoting elements secured to the base of the syringe. The pivoting elements move outwardly from each other to allow use of the syringe. The pivoting elements pivot through about 180 degrees so they are disposed alongside the barrel of the syringe.
U.S. Pat. No. 4,950,249 (Jagger et al.) discloses another type of hypodermic needle apparatus in which there are a pair of elements that are pivotally secured to the base of the syringe. There is a hub ring or a ring hub, and the pivoting elements are molded as part of the hub in their open position. Accordingly, when the sheath elements are pivoted to the closed position, there is an inherent bias in the material to urge the sheath elements to their open position. When the sheath is open, the elements move outwardly or pivot outwardly substantially 90 degrees to allow use of the syringe apparatus.
U.S. Pat. No. 5,139,489 (Hollister) discloses a needle protective cap which pivots on a living hinge relative to a bottom element. Hollister's U.S. Pat. No. 5,154,285 discloses similar apparatus.
U.S. Pat. No. 5,151,089 (Kirk et al) discloses a protective sheath for a syringe that pivots relative to a support base which is secured to the syringe assembly.
The apparatus of the present invention differs from the prior art in its structure. While there are elements of the prior art, as discussed above, that include only a single element, most of them utilize a pair of elements which move in a clam shell type pivoting arrangement from the closed position in which they form a shield for a needle to their open position for use of the syringe and needle. The apparatus of the present invention includes several embodiments which include only a single pivoting element. In practically all cases, there is a guard element which moves about a sheath element for covering and uncovering a slit in the sheath element through which the needle may pass. The pivoting action of the shield apparatus of the present invention is different from the prior art elements and accordingly provides a positive lock in the open position in several embodiments.
It will be noted that while the drawing figures and the specification refer primarily to needles of hypodermic syringes, the apparatus of the present invention applies to all instruments in which a needle is attached to a fluid element for the transfer of liquid material, such as vacutainers, cannulae, and the like.
Moreover, the shield apparatus of the present invention is primarily a needle guard, or is primarily associated with a needle rather than with the syringe, per se. In the circumstances where a needle and syringe are prejoined by a manufacturer, the apparatus is naturally associated with both.